Taking care of your newly installed sod properly is key to establishing a healthy, thriving lawn space. After installing fresh sod, most clients will ask us “so how often should I water?”. This can be a tricky question to answer as there are several factors to consider:
Time of year
Weather forecast
Watering method
Lifestyle factors (work schedule, vacations etc.)
There is no one size fits all answer to this question, however, there are some key variables that will help you determine the best approach for you. First and foremost, new sod will require regular watering for 3-4 weeks after installation. The City of Calgary allows for a 21 day restriction free watering period for new sod, but be sure to check the city website for up to date information on water restrictions.
Week 1:
During the first week water your new sod twice a day for about 20 minutes each, or around 30 minutes if you only have time for one application. This period is critical for the establishment of the root system as the sod will have been recently harvested, transported, and stored in the sun, and will be in desperate need of consistent moisture. A good way to check that water has penetrated into the subsoil is to lift an accessible corner of a piece of sod to see if the soil underneath is wet. If you water for the recommended amount of time and the subsoil is still dry, continue watering until it is sufficiently saturated. It should be moist, but not soggy or muddy.
You must limit foot traffic in the area for 2-3 weeks as the topsoil will still be spongy and needs time to settle. Walking on the new sod, especially after watering, can lead to lumpiness in the freshly graded soil which may require topdressing to fix later on. If watering twice a day, do so in the morning and late afternoon or early evening, as watering during the hottest, sunniest part of day can prevent the moisture from absorbing into the soil before it evaporates, and strong winds can cause water to drift away from its intended location. If watering once a day, do so either in the morning or late afternoon/early evening depending on your schedule. Watering late in the evening can leave the grass wet overnight which promotes fungal growth so early morning and late afternoon are best to allow for sufficient absorption.
Leaving sod unwatered during this critical period can result in drying out, and ultimately death of patches, edges and corners, or the entire lawn.
Week 2:
Continue watering 1-2 times a day during this week, and continue to periodically lift corners of different pieces of sod to check for soil moisture. Lifting these corners will also allow you to see if the sod has started setting new roots. When you feel some resistance from the sod when lifting, this means that the new roots have started to take hold and you should start leaving it alone to avoid further disturbance. Lift corners from different pieces throughout the first two weeks to make sure the same section is not being repeatedly disturbed.
Week 3:
At this point your sod should have some new roots growing in. You will still need to water 3-4 times per week for 20-30 minutes per application. Longer, less frequent waterings encourage roots to penetrate deeper into the soil which will allow them to access deeper reserves and survive longer between waterings. Allow the grass to get 3-4 inches long before mowing as mowing too soon will encourage top growth instead of root growth.
Week 4:
Continue watering 3-4 times per week. Now with some new root growth, you can consider application of a starter lawn fertilizer. These will typically have a high middle number (phosphorous), to help encourage root growth. Some people ask about applying fertilizer right after installation, however, we recommend waiting 3-4 weeks to allow new root growth to establish in order to make the most of the fertilizer application. Applying a high nitrogen (first number: N-P-K) fertilizer immediately after installation will encourage more top growth and divert energy from root establishment where it is needed during that time.
Beyond:
Now you should have a healthy, established new lawn! From here, continue watering for 15-25 minutes about 3 times a week. Be sure to check the City of Calgary website for your prescribed watering schedule if any restrictions are in place. Remember, watering durations are estimates only, and you must calibrate your watering schedule to your specific needs. Key considerations include:
Delivery Method:
Irrigation system?
Talk to your irrigation company to help determine optimal watering schedule based on your flow rates and zone coverage.
Hose & Sprinkler?
Be sure that your sprinkler is reaching all areas of your lawn space. You may need to move it around and water different sections separately which will add to your overall watering time each day.
If your sprinkler is covering a large area, you may need to extend the watering time to ensure adequate coverage. Since the same flow rate from your hose will be covering a larger area, there will be less water delivered to each square foot. Remember to spot check by lifting a corner to check soil moisture underneath the sod.
By Hand?
Not recommended but can work for small spaces.
Timing can vary, but you will likely want to water each piece of sod for 1-2 minutes with a spray nozzle on the shower setting. Check soil moisture to help determine optimal timing for your hose and spray nozzle.
Time Of Year And Weather Conditions:
Keep an eye on the forecast and be sure to check projected rainfall amounts. Remember that new sod requires a lot of water, and even if it rains, it may not be enough to penetrate the subsoil. New sod will require 1-2” (25-50mm) of water per week, so if it only rains 1-2mm on a given day, you will still need to water. Established lawns require about 1” (25mm) of water per week.
The average flow rate for residential hoses in Calgary is about 17 litres per minute. Over a 500 square foot area (46.5 square meters), a 20 minute application will deliver about 7.3mm of water. To get 25mm of water per week, you will need to water for 20 minutes, 3-4 times a week.
Keep in mind that on hot days, especially in July and August, new sod can dry out extremely quickly so keep a close eye and don’t hesitate to add an additional application during the day if things are looking dry. Similarly, on cool, cloudy days, it will hold moisture for longer and may not require as much water.
As you can see, there is no perfect answer to the question “so how often should I water?”. Overall, these basic guidelines should be sufficient and adaptable to most scenarios in Calgary: Weeks 1 & 2: water 20-30 minutes 1-2 times a day, limit foot traffic. Weeks 3 & 4: if roots are getting started, reduce watering to around 30 minutes 3-4 days per week. Wait to mow until grass is 3-4” long. Apply a starter fertilizer after the establishment period is complete.
Leave your comments below and feel free to reach out if you have any questions about getting your new lawn started!
References
Marion Soil and Water Conservation District. (2012). Planting & Maintaining Your Lawn. Marion Soil and Water Conservation District. https://www.marionswcd.net/wp-content/uploads/2022/01/Planting-Maintaining-Your-Lawn-RWPC.pdf
The City of Calgary. (n.d.). Lawn and landscaping watering schedule. The City of Calgary. https://www.calgary.ca/water/drought/lawn-watering-schedule.html
The City of Calgary. (n.d.). Saving water in your home. The City of Calgary. https://www.calgary.ca/water/programs/saving-water-in-your-home.html
